Bridge and method of building the same



May 7, 1963 G. THIMAN BRIDGE AMD METHOD OF BUILDING THE SAME Filed Oct.20, 1958 ged states invention relates to bridges, and particularroadwayis carried The present ly to the type of bridges in which a on or bycables or wires.

The main object of the invention is to provide a bridge of reinforcedconcrete which can be built more rapidly and at a lower cost than priorbridges comprising roadways of concrete.

A further main object of the invention is to provide a method forbuilding bridges of the type referred to in a simple and eicient mannerat a relatively low cost.

The bridge, according to the invention, comprises suspension cables orwires and means for anchoring the ends thereof at the ends of the bridgeand, further, a roadway of concrete in which the cables or wires areembedded as reinforcements. Supporting cables may be extended betweenthe anchoring places of the bridge prior to the moulding of the roadway,whereby said cables can be utilized for supporting the mould in whichthe roadway is moulded. Not only the suspension cables may be utilizedas reinforcements for the concrete, but also the mould itself, since thelatter may remain in the moulded roadway as a structural elementreceiving the stresses and strains applied to the bridge in use.

Other objects and features of the invention will more clearlyhereinafter appear by reference to the accompanying drawing forming apart of the specification and wherein like characters of referencedesignate corresponding parts throughout the several views, in whichFIG. l is a vertical elevation showing the bridge from one side thereof,

FIG. 2 is a transverse section on an enlarged scale, taken on lines 2-2of FiG. l,

FlG. 3 is a transverse section similar to that shown in FIG. 2 butrelating to a modified embodiment of the invention,

FIG. 4 is a detail of FIG. 3 shown on an enlarged scale,

FIG. 5 is a bottom view of a detail of FIG. 4,

FIG. 6 is a fragmentary section of a detail which is a modification ofthe detail shown in FIG. 4,

FIG. 7 is a transverse section similar to that shown in FIG. 2 butrelating to a further embodiment of the invention.

FlG. 8 is also a transverse section similar to that shown in FIG. 2 butrelating to a still further embodiment of the invention,

FIG. 9 is a transverse section of the roadway during moulding, and

FIG. l0 is a fragment of a longitudinal section corresponding to FIG.9'.

The invention would be most easily understood by a description of themethod for building the bridge. First, it should be noted that FIG. lillustrates a bridge comprising two piers l and 2 as supports for theroadway or top structure but that such supports can be omitted.Alternatively, any other suitable number of piers could be used, thenumber being dependent upon the length of the bridge.

Suitably, the pier structures 1 and 2 are rst built, for example, fromreinforced concrete. A layer of steel cables or wires 3 are then mountedto extend from one shore anchorage 4 over the piers 1, 2 and to theother shore anchorage 5, the ends of the cables or solid wires beingembedded into concrete anchorages or secured to fic 3,088,245 PatentedMay 7, 1963 the anchorages in any other suitable manner. The cables orwires 3 are referred to hereinafter as supporting means or supportingcables.

A roadway is now built on the supporting cables by mounting a mould onthe top of the cable layer, said mould being then used for themanufacture of a roadway of reinforced concrete. As shown in FIG. 2, thebottom of the mould may consist of sheet metal pieces 6 extending overthe entire breadth of the bridge. A plurality of steel sheets may bewelded together to form an integral web extending from one end of thebridge to the other. Lateral members 7 and 8 in the form of U-shapedgirders or bent sheet metal strips are mounted on the longitudinalmarginal portions of the bottom web to form the sides of the mould. Thelateral members 7, S are connected by transverse truss rods 9. Steelcables or wires 10 are mounted in the mould to form reinforcements.These cables or wires may extend from one anchorage -4 to the other 5and be secured to these anchorages, or each individual cable may extendonly for a part of the length of the bridge. They may consist of wiresthat are corrugated or undulated at their end portions or along theirentire length. Concrete mass 10' is now poured into the mould so thatthe cables or wires 10 will become embedded into the concrete asreinforcements.

The mould may advantageously remain to form a part of the carryingstructure of the bridge. In such case, the mould and the concrete forman integral unit in the roadway adapted to receive the stresses andstrains caused by the weight of the roadway itself and by the loadthereon, as well as by lateral wind forces.

Since it would be diffiicult to eifect the moulding of the bridge in onesingle operation within the period of setting of the concrete, therewould be a risk of uneven deflection of the roadway during the mouldingoperation so that it could deviate from the catenary form. This may beavoided by mounting additional truss cables or rods 11 and 12 betweenthe bases of the piers 1, 2 and the roadway, as shown in FIG. l. Thetruss rods may contain turnbuckles such as 14 allowing reduction oftheir length to apply downward tension on the roadway mould. Torsionaldeiiection of the mould may also be counteracted by performing thecasting operation successively in steps, each step comprising themoulding of a longitudinal strip or section of substantially the samelength as the bridge but corresponding to only a portion of the breadththereof. The concrete may be applied by blowing the concrete throughlongitudinal tube lines along the entire length of the bridge. After onelongitudinal concrete section has been cast, the tube lines may be movedto blow out concrete for a further section laterally of the rst sectionand so forth.

The truss rods or cables 1X1 `and 12 may be mounted so as to allowdownward pull on the suspension reinforcements or cables l, whereby thecables '10 may be prestressed during the moulding operationsubstantially like the reinforcements in prestressed concrete. After themoulding operation has come to an end, the truss rods should betightened further, for example, by the turnbuckles 14. The truss rods 12which are attached to the roadway relatively near the central portionthereof may be removed after the concrete has set. The truss members 11located nearer the piers should be maintained under their own tensionwith a View to eliminating oscillations of the bridge.

The mounting of the wires or cables 10 in the mould may be facilitatedby using a wooden mounting table 15, the top surface 16 of which issubstantially straight and horizontal as indicated in FIG. l. Thismounting table rests on the bottom of the mould while the wires 10 arelaid out on the top of the mounting table. The Wires 10 are suitablystretched between the anchorages 4, but only to a certain relativelylittle extent. The ends thereof are secured to the anchorages. The endsof the Wires or the entire wires may beof sinuous shape (cf. FIG. orthere may be anchoring means such as rings or sleeves secured to theends of the wires which are embedded into the anchorages 4 and 5. Themounting table is removed, after the wires have been mounted and, as aresult, the wires will sag and be stretched longitudinally due to theirown weight. If desired, suitable tensioning members may be attached tothe Wires and secured to the transverse truss rods 9 or the bottom ofthemould to allow further stretching of the fwires 10 by pulling themtowards the bot-tom of the mould to a suitable distance therefrom, aswill be further described with reference to FIGS. 9 and 10. Concretemass is then poured into the mould and allowed to set, the tensioningmembers being embedded into the concrete in their stretched state.

Since the mould is cast permanently to the concrete to form an integralstructure and remains in the roadway as a structural element takingupload, no particular costs for additional mould means are required.This results in a considerable saving of cost and material.

The supporting cable 3 may be omitted, if the bottom of the mould iscomposed of at steel strips extendingadjacent one another from oneanchorage 4 to the'other 5. A transverse section of a bridge of thisconstruction is illustrated in FIG. 3, -wherein the bottom strips aredesignat- 4 bridge, the span of which may amount to about 330 yards andtotal length to 545 yards.

In FIGS. 9 and 10, tensioning members in the form of ear bolts areprovided to enable stretching of the longitudinal wires 10 in the mould6, 7, S before pouring concrete mass into the latter. Transverse rods 26extend through the ears of the bolts 25 and rest on the wires which arelocated in twosuperimposed layers. The bolts are carried through smoothholes in the bottom pieces 6 of the mould, and are adapted to be pulleddownwards by turning nuts `27 on the lower ends of the bolts, wherebythe wires 10 may be stretched and adjusted to take their correctposition relatively to the bottom of the mould. FIG. 10 also illustratesnndulated portions 2'8of the wires -10 as wellas weld joints 29 betweenthe transverse edges y of thebottom steel pieces 6 referredtohereinbefore.

Since I have described hereinbefore various forms which the roadway ofthe .bridge may take and various modifications of the details, it willbe understood that I do not intend to limit myself to the specific formsof the invention shownherein but intend to claim the invention asbroadly as may be permitted by the state of the prior art and the scopeofthe following claims.

ed by reference Vnumeral 17. 'Ihe strips are held on the same level bybolts '118 located between the adjacent edges `of Ythe strips 17 andcarried through holes in sealing strips 19 overlapping the space betweenthe edges of the strips 17. The heads 20 of the bolts may be of aspecial elongated shape, as shown in FIGS. 4 and 5, whereby the boltsmaybe easily inserted between the strips y17 from above after the stripshave been adjusted into their correct position. The Ibolts are tightenedfrom above by nuts 21 remain in the roadway after the concrete has set,thus the strips contribute to the strength of the bridge.

A modified arrangement for keeping the bottom strips bottom of thestrips 17, respectively. ,Y FIG. 7 illustrates a still further form ofthe bottom of the mould which, in this case, is composed of a-pluralityof overlapping steel bands 2.2, all of them -suitably having equalbreadth.

FIG. 8 illustrates a cross section of a further embodiment of roadwaywhich is similar to that shown in FIG. 2 Y but in which transverse beams23 are mounted below the supporting cables 3. By Way of example, itcould be mentioned that sixteen beams 23 may be mounted in spacedrelation and distributed along the length Vof-the K vwhich also Willpress the sealing strips 19 firmly-on the A lbottom strips v17. Thestrips 17 and '19 are intended to `17 in correct mutual position and forobtaining seal be- Whatis claimed is:

A bridge comprising shore anchorage means, a plurality of steel bandsconnected together along their adjacent edges to vform a continuousbottom, means for coupling said bottom at its opposite ends to saidshore anchorage means, at least two piers positioned between the shoreanchorage means and supporting intermediate portions of said bottom, thebottom being suspended along a catenary curve from said piers, aconcrete roadway carried and reinforced by said steel band bottom, trussrods each connected at one end toone of the piers and at the oppositeend to said bottomto apply downward tension to the latter, reinforcingcables having their ends coupled to said anchorage means and embeddedvinthe concrete roadway to further reinforce the roadway, and a pluralityof tensioning means each connected from an intermediate part of areinforcing cable to the adjacentfunderlying point on the bottom forapplying tension to the reinforcing cables.

References Cited in the iile of this patent UNITED STATES PATENTSSchauwecker lune 4, 1907 Germany Sept. 6, 1956

